Simple se ideas

[gazzgary]

Hi all,

I have had some simple se boards I have ordered from George sitting in my study for a while and have decided to get motivated and start building.

I need to order everything except for those impossible to get 'transistors' I have successfully built a few pcb based tube amps now and want to go a bit further with this one.

My idea is to use the new kt120 tube driven pretty much to maximum dissipation and I'm hoping to get 20 or more watts in ultralinear mode using diode rectification only.

I would like to use one of the antek toridal power transformers and wanted to get some opinions on what the absolute maximum voltage I could apply to the board would be I'm quiet aware that I would need to series up power supply caps if the rectified voltage gets to be more than 500 but unsure if any resistance values should change for the driver tubes.
Or weather sticking to the max recommended 400-0-400 would be the go

For the outputs triode store has a pretty good looking 30w single ended ultralinear transformer 2.5k or using different tappings 5k I was thinking this would be pretty good configured to use it as 2.5k

Just wanted to throw some ideas around and see what people thought.

Gary

Ps I have accidentally posted this to the main forum and can't seem to delete it

[rknize]

I don't think is a practical limit to the PCB itself. You'd want to check the working voltages of R2 and R4. You also might want to increase the values of R14/24 to take some of the thermal stress off of the CCS (you can also increase the size of their heatsinks). That's all I can think of off the top of my head.

[Jpeg]

I don't know if you saw them, but there are at least 2 threads on this already.

Simple SE with kt120?

Simple SE with KT120s

I have to admit that this idea has been rattling around in my head ever since I got my grubby hands on a pair of Edcor's mamoth single-ended output transformers. ( EDCOR Electronics Corporation. CXSE25-8-5K I have been listening to it's 3.2k brother for the last week on 2a3s and 300b's and they sound very nice especially for the price. I am not sure what the ideal plate load would be for a KT120, I would do more research before moving forward) That, or taking two simple SE boards and making SE monoblocks with 2 Kt88 or EL34's per channel. From these threads it sounds like two of the biggest challenges will be finding caps that will take that much voltage, and keeping octal base sockets from arcing. Of course there is always the danger of the kt120 not catching on, and spending a lot of time and money on an orphan amp. And I agree with George, get the amp running first, then put in the KT120, then turn up the voltage, there would be too many variables otherwise. I would love to see someone actually build one. Hmmm, I do have a simple SE board just laying around...

[VictoriaGuy]

Originally Posted by gazzgary

I need to order everything except for those impossible to get 'transistors' ........

What are those? I have a simple SE board and a few parts in a box here -unbuilt- and just assumed I could easily source more parts if needed.

[rknize]

Probably the CCS. You might try hitting up Pete Millett. He bought a bunch to ship to overseas folks that can't get them. It's mainly for his "red board", but he'll probably sell them to whomever.

[deadpool]

Just an idea, how about sourcing iron from...

Audio Catalog

I used the Mars iron and its very well priced to get to Australia and sounds good too